doc: remove deprecations from pytest 3

This is in line with 9c5da9c, which versionadded instructions.

Author: blueyed

doc/en/deprecations.rst

@@ -575,40 +575,3 @@ As a stopgap measure, plugin authors may still inject their names into pytest's
 
     def pytest_configure():
         pytest.my_symbol = MySymbol()
-
-
-
-
-Reinterpretation mode (``--assert=reinterp``)
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-
-.. versionremoved:: 3.0
-
-Reinterpretation mode has now been removed and only plain and rewrite
-mode are available, consequently the ``--assert=reinterp`` option is
-no longer available.  This also means files imported from plugins or
-``conftest.py`` will not benefit from improved assertions by
-default, you should use ``pytest.register_assert_rewrite()`` to
-explicitly turn on assertion rewriting for those files.
-
-Removed command-line options
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-
-.. versionremoved:: 3.0
-
-The following deprecated commandline options were removed:
-
-* ``--genscript``: no longer supported;
-* ``--no-assert``: use ``--assert=plain`` instead;
-* ``--nomagic``: use ``--assert=plain`` instead;
-* ``--report``: use ``-r`` instead;
-
-py.test-X* entry points
-~~~~~~~~~~~~~~~~~~~~~~~
-
-.. versionremoved:: 3.0
-
-Removed all ``py.test-X*`` entry points. The versioned, suffixed entry points
-were never documented and a leftover from a pre-virtualenv era. These entry
-points also created broken entry points in wheels, so removing them also
-removes a source of confusion for users.